Can't find the Camshaft Position Sensor

[A91EBexplorer4x4]

i'm pretty daggon pissed about not knowing whats wrong with my truck. I have a 1991 4dr with the 4.0L pushrod engine and a standard transmission. well it just out of the blue stopped running and now won't start it will turn over. a few times it backfires out the pipe or it will backfire through the intake. im thinking that it is the camshaft position sensor which sends the signal to the main comp. PCM i believe it is. that tells it to spark and when to shoot the fuel.
i have fuel i have sparks the batter is good i checked the coil pack with the ohm meter and its ok.
Where is the Camshaft Position Sensor?


Please help me!!!!!

 

[SteveVB]

You dont have one

Fed 91s dont have a camshsft position sensor- the CA emmissions might tho Im not sure. I believe they started to use them in 94 , if you did have one it is at the rear of the engine, on the top of the block behind the manifold.

Timing is controlled with the pickup at the front left of the harmonic balancer. at about the 10 or 11 oclock position. Its called a VR or VRS ( variable reluctance sensor) and it gets its signal from the 35 tooth wheel on the Harmonic balancer. This with your coil pack and the EDIS module, and the EEC control the ignition.

Have you pulled the codes yet- it should be your first step.

Have fun and good luck.

 

[A91EBexplorer4x4]

ran self tests

All i di was do the self test by jumping the wires and then counting the number of check engine light flashes but nothing came up. in the haynes manual it doesnt really specify that what year the CPS camshft position sensor started. but it does talk about a sensor by the crank, but says it doesnt control the timing as far as spark and fuel. ill look into it a bit more though. thanks for the tip.

 

[A91EBexplorer4x4]

help still

still need some help. anyone ..





Bump

 

[SteveVB]

If you are not getting any codes then I would check the grounds to the coils, edis. Also check the VRS, its wiring harness, the connector, and voltage to it (1.5 on koeo).

No matter what the haynes manual says the vrs relays the position of the crankshaft for the timing control.

Haynes is not a great source - if you are doing real work on your vehicle I would get a service manual from Ford- most of the third party manuals leave a lot of information out once you get past changing simple sensors, oil etc. They have very poor diagnostic info, which the factory manuals have in great detail- best money you will spend on a vehicle IMO.

 

[Paul Gagnon]

The VRS is the CRANKSHAFT position sensor. It is located on the passenger's side front of the engine near the bottom. It has a pointy piece that sticks out close to the harmonic balancer. This is a conpletely passive component and most likely is not the source of your problem.

If you are not getting any codes I doubt that it is the VRS. I had a similar problem with mine and after many dollars and replacing every component in the ignition system it turned out to be the computer. If you can get another computer you'd be better off going that route than spending all the money on the coil, VRS, TFS module etc just to find out that your computer is bad and now you have spares of all these parts that will probably never fail.

 

[A91EBexplorer4x4]

you won STEVEVB

well steve you won man it was the sensor right at the harmonic balance pulley although what ever the name of it is
seems we all have a few so far. anyways it was broken off and still connected to the electrical plug so thats why i didnt get a code for it but in that no good haynes manual it did not specify that it didnt have the camshaft sensor but it did say that it did, so i just kinda concentrated on that. a big chunk of ice from a water hole i was crossing (when it died ) must have broken it. no more 2" thick icy water crossings for me. right now i have it super glued together but i doubt that will hold up.you guys have a crankshaft sensor?
Thanks for your help!